JP2006278383A - Solid state laser device and laser device system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To stabilize the output state of an output light having been wavelength-converted by blocking the heat generated at a semiconductor laser or laser material from affecting a wavelength conversion element. <P>SOLUTION: In a solid state laser device of semiconductor laser excitation type, a semiconductor laser beam is radiated in the side direction of a laser material 6 for excitation to provide a laser output using an optical resonator, and the laser output is wavelength-converted by a wavelength conversion element 3. The wavelength conversion element 3 performs phase matching by refractive index. A basic wave laser is thermally separated from the wavelength conversion element 3, which is separately controlled for temperature. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a solid-state laser device and a laser device system.

  Recently, the use of solid-state lasers has been intended as “light sources for laser printers, laser scan displays, projectors, etc.”, and “semiconductor laser excitation type high-power solid-state laser devices” are in line with the demand for miniaturization of solid-state laser devices. It is being developed.

  As a solid-state laser device with excellent heat dissipation effect, the laser material is thinned, laser light from a semiconductor laser is incident from the side surface of the laser material and excited, and laser light is emitted by a resonator provided close to the laser material. The thing of a structure is known (patent document 1, 2). Since a semiconductor laser as a light source for excitation light has a limited light emission performance, a laser beam from a plurality of semiconductor lasers is often incident from different directions to obtain a necessary amount of light.

  Laser light having a desired wavelength can be obtained by further converting the wavelength of the laser output obtained from the laser material through a wavelength conversion element. The wavelength conversion element is generally "one that performs phase matching by refractive index". However, in such a wavelength conversion element, the refractive index tends to change sensitively due to temperature changes, and when the refractive index changes, the wavelength is converted. The output state of the output light becomes unstable.

  In order to make the solid-state laser device compact, laser materials, semiconductor lasers, wavelength conversion elements, etc. need to be laid out in a compact layout. However, since laser materials and semiconductor lasers generate heat during operation, There is a problem that the wavelength conversion element is easily affected. In particular, when a plurality of semiconductor lasers or a semiconductor laser array is used as the excitation light source, the amount of heat generated by these light sources also increases.

  As a method of reducing the influence of the heat generated by the laser light source or semiconductor laser on the wavelength conversion element, it is conceivable to forcibly cool the semiconductor laser or laser material that is the heat source, but the semiconductor that uses the wavelength conversion element as the heat source When loaded on the same substrate as the laser or laser material, it becomes difficult to control the temperature of the wavelength conversion element.

Patent No. 3503588 USP 5553088

  In view of the above-described circumstances, an object of the present invention is to make it difficult for heat generated in a semiconductor laser or a laser material to reach a wavelength conversion element, and to stabilize the output state of wavelength-converted output light.

  The solid-state laser device of the present invention is “a semiconductor laser excitation type in which semiconductor laser light is incident and excited from the side surface direction of a laser material, laser output is obtained by an optical resonator, and the resulting laser output is wavelength-converted by a wavelength conversion element. The solid-state laser device has the following characteristics (claim 1).

  That is, the wavelength conversion element is “one that performs phase matching based on the refractive index”, and the fundamental wave laser unit and the wavelength conversion element are thermally separated, and the temperature is controlled separately.

The “laser material” is a material obtained by doping an additive with a crystal material such as GdVO ₄ or a ceramic material such as YAG, as is widely known in connection with solid-state laser devices. : GdVO ₄ (neodymium: gadonium / vanadium oxide), Nd: YAG (neodymium: yttrium / aluminum / garnet), Nd: YVO ₄ (neodymium: yttrium / vanadium oxide), Yb: YAG (ytterbium: yttrium / aluminum / garnet) Etc. can be used suitably. In the above, Nd and Yb are additives, which are doped into YAG or the like, and are excited by absorbing excitation light to emit light. Thus, the emitted light resonates by the optical resonator to generate laser light. The laser output outputted from the laser material in this way is called “fundamental laser beam”.

  The “optical resonator” may be “formed as a reflective film” directly on the opposing surface of the laser material, or at least one reflective surface may be arranged separately from the laser material.

  In the above explanation, “semiconductor laser light is incident and excited from the side direction of the laser material” means that the excitation light from the semiconductor laser is “emitted on the optical axis of the optical resonator (the direction in which the fundamental laser light is emitted)” It means that the light is incident on the laser material from “perpendicular or nearly perpendicular direction”.

The “wavelength conversion element” performs phase matching by the refractive index. Specifically, “periodic polarization inversion type MgO: LiNbO ₃ (magnesium oxide: lithium niobate)” can be preferably used, and periodic polarization can be used. Inverted MgO: LiTaO ₃ (magnesium oxide: lithium / tantalum oxide), KTP (KTiOPO ₄ ), KN (KNbO ₃ ), or the like can be used.

  The “fundamental wave laser part” is a structural part for generating laser light to be wavelength-converted by the wavelength conversion element.

  The wavelength conversion element in the solid-state laser device according to claim 1 can be fixed to a “cover portion covering the fundamental wave laser portion” (claim 2). In this way, by interposing a heat insulating member between the cover part and the fundamental wave laser part, it is possible to effectively prevent heat from the fundamental wave laser part from affecting the wavelength conversion element due to heat conduction through the cover part. be able to.

  In the solid-state laser device according to claim 2, a temperature adjustment element can be interposed between the wavelength conversion element and the cover (claim 3). With this configuration, the temperature of the wavelength conversion element is controlled by the temperature adjustment element. It can be adjusted to a desired temperature.

  The solid-state laser device according to any one of claims 1 to 3 can include a “light condensing element that condenses laser light traveling from the fundamental wave laser unit to the wavelength conversion element” (claim 4). In this case, the condensing element can be provided on the fundamental wave laser part side (Claim 5), or can be provided on the cover part side (Claim 6). By condensing the laser beam (fundamental laser beam) from the fundamental wave laser part to the wavelength conversion element using the condensing element, the laser beam from the fundamental wave laser part is substantially converted to a 100% wavelength conversion element. The light can be taken in and the light use efficiency can be increased.

  The solid-state laser device according to any one of claims 1 to 6 can include an “optical path bending element that bends the optical path of laser light from the fundamental wave laser unit to the wavelength conversion unit” (Claim 7). By using the optical path bending element, the degree of freedom in the layout of the wavelength conversion element with respect to the fundamental laser unit in the solid-state laser device is increased. In particular, the longitudinal direction of the wavelength conversion element can be set in a direction parallel to the substrate of the fundamental wave laser unit, and the solid state laser device can be thinned.

  Further, the optical path bending element in the solid-state laser element according to claim 7 can also serve as a “condensing element having a condensing function and condensing laser light from the fundamental wave laser unit toward the wavelength conversion element” (claim) Item 8).

  When the solid-state laser device according to any one of claims 4 to 8 has a condensing element that condenses laser light directed from the fundamental wave laser unit to the wavelength conversion element, the condensing element has a “condensing function”. It can be configured to be “adjustable” (claim 9).

  The optical path bending element in the solid-state laser device according to claim 7, 8, or 9 can be “provided on the cover side” (claim 10). In this case, the optical path bending element has “a condensing function that can be adjusted by temperature”. In addition, a temperature adjusting element can be interposed between the cover portion and the cover portion (claim 11).

  The solid-state laser device according to any one of claims 1 to 11 can be configured as “a microchip laser configuration in which an optical resonator is formed of a reflective film formed on an opposite surface of a laser material” (claim 12). .

  The laser device system of the present invention is a laser device system using the solid-state laser device according to any one of claims 1 to 12 (claim 13).

  As a supplementary explanation, an optical lens such as a microlens can be used as the “condensing element”, and a known appropriate optical device having a condensing function, such as a concave mirror, a gradient index lens, and a liquid crystal lens. An element can be used.

  In addition, the “light condensing element with adjustable light condensing function” can be realized by making an optical lens such as a microlens movable in the direction of the optical axis, or by “a liquid crystal lens with adjustable lens power”. It can also be realized, and further, it can be realized as “the curvature of the mirror surface of the concave mirror is changed by the action of heat or mechanical force”.

  As the “optical path bending element”, a mirror or a prism can be used. As the “optical path bending element that also serves as a condensing element”, the concave mirror described above, “a lens surface formed on an incident surface or an exit surface of a prism”, “a liquid crystal lens attached to a reflecting surface”, or the like is used. Can do.

  Further, the temperature control of the fundamental wave laser unit may basically be “cooling”.

  As described above, in the solid-state laser device of the present invention, the wavelength conversion element is “one that performs phase matching based on the refractive index”, and thus is sensitive to temperature changes. Since these are separated and temperature controlled separately, it is possible to effectively reduce or prevent the heat generated in the fundamental laser part from affecting the wavelength conversion element, and the wavelength-converted output light can be kept stable. It becomes possible to obtain.

  Hereinafter, embodiments of the invention will be described as examples.

FIG. 1 is a diagram for explaining the first embodiment.
FIG. 1A is a plan view of the fundamental wave laser unit, and FIG. 1B shows an end face of a side cross section of the solid-state laser device.

  As shown in FIG. 1B, semiconductor lasers 1A and 1B, excitation light condensing lenses 2A and 2B, and a laser material 6 are provided on a base substrate denoted by reference numeral 14. Submounts 8A, 8B, and 9 are provided on the upper surface of the substrate base 14, the semiconductor laser 1A is provided on the submount 8A, the semiconductor laser 1B is provided on the submount 1B, and the laser material 6 is provided on the submount 9. ing.

  The optical resonator is formed by vapor deposition or the like as a “reflective film” on two opposing surfaces of the laser material 6, that is, two surfaces in the vertical direction in FIG. That is, the laser material 6 formed with the reflection film as an “optical resonator” in this way has a “microchip laser configuration”. The base substrate 14, the semiconductor lasers 1A and 1B provided thereon, the excitation light condensing lenses 2A and 2B, the laser material 6 integrally formed with the optical resonator, and the submounts 8A, 8B, and 9 are “basic”. The “wave laser unit” is configured.

  Further, a cooling means 100 is provided on the lower surface side of the base substrate 14 so as to forcibly cool the fundamental wave laser part. In the first embodiment, the cooling means 100 is “a water-cooled type that cools the inside through cooling water”, but may be an air-cooled type, or a heat pipe method or an electronic cooling method (Peltier method) is used. You can also.

  As shown in FIG. 1B, the upper part of the fundamental wave laser part is covered with a cover part 16, and a heat insulating member 15 is interposed between the base substrate 14 and the cover part 16 of the fundamental wave laser part. Thus, the fundamental laser part and the cover part 16 are “thermally separated”.

  The wavelength conversion element 3 is held at the center of the cover portion 16 so as to be positioned above the laser material 6. The cover part 16 is also provided with a Peltier element 110 as a “temperature adjusting element”, and the temperature of the wavelength conversion element 3 is maintained at a desired temperature through the cover part 16.

  More specifically, the semiconductor lasers 1A and 1B that emit excitation light have an emission wavelength of 808 nm, and the laser material 6 is YAG (yttrium, aluminum, garnet) doped with Nd (niodymium). is there. Of the reflective films constituting the optical resonator, the reflective film on the side in contact with the submount 9 is set to reflectivity: 99%, and the reflective film on the opposite side is set to reflectivity: 97% (ie, transmittance: 3%). Is set to

  In such a configuration, when laser light is emitted from the semiconductor lasers 1A and 1B, the emitted laser light is condensed as excitation light by the action of the excitation light condensing lenses 2A and 2B. Is irradiated into the laser material 6 from the side surface of the laser beam, and the light condensed and excited at the substantially central portion of the laser material 6 is resonated by the optical resonator to generate stimulated emission, thereby obtaining a fundamental wave laser beam having a wavelength of 1064 nm. Can do. Note that the additive Nd is doped at a high density in the “center portion of the laser material 6” where the excitation light is condensed.

The wavelength conversion element 3 is made of a periodically poled type MgO: LiNbO ₃ (magnesium oxide: lithium niobate), and the fundamental wave laser beam having the above-mentioned wavelength: 1064 nm is obtained by “phase matching by refractive index”. / 2 wavelength: wavelength converted to 532 nm laser light and output.

  As described above, the base substrate 14 of the fundamental wave laser unit is controlled to be cooled by the cooling unit 100, and is thermally separated from the “cover unit 16 that holds the wavelength conversion element 3” by the heat insulating member 15. Since the temperature of the wavelength conversion element 3 is maintained at a desired temperature through the cover portion 16 by the Peltier element 110 provided as a temperature adjustment element, the temperature of the wavelength conversion element 3 can be stabilized, and the wavelength converted wavelength: 532 nm Can be stably output.

FIG. 2 is a diagram for explaining the second embodiment. In order to avoid confusion, the same symbols as in FIG.
The difference between the second embodiment and the first embodiment is that a temperature adjusting element 13 is interposed between the cover portion 16A and the wavelength conversion element 3 held by the cover portion 16A. The temperature of 3 is adjusted directly. Other parts are the same as those in the first embodiment.

  The temperature adjustment element 13 is a Peltier element, and maintains the temperature of the wavelength conversion element 3 at a desired temperature. Compared with the case of the first embodiment, the temperature adjustment element 13 directly adjusts the temperature of the wavelength conversion element 3, so that the temperature of the wavelength conversion element 3 is made "higher accuracy" than in the case of the first embodiment. Can be adjusted.

FIG. 3 is a diagram for explaining the third embodiment. In order to avoid confusion, the same symbols as in FIG.
The difference from the first embodiment is that the “portion holding the wavelength conversion element 3” of the cover portion 16B is slightly extended “to the laser material 6 side”, and the extended portion is a “condensing element” as a condensing lens. 5 is held. Other parts are the same as those in the first embodiment.

  The condensing lens 5 is held between the laser material 6 and the wavelength conversion element 3 above the laser material 6, and transmits the fundamental laser beam from the laser material 6 to “the central portion of the wavelength conversion element 3 in the length direction”. The light is condensed so that a beam waist is formed in the vicinity, and is incident on the wavelength conversion element 3. The laser light incident on the wavelength conversion element 3 in this way is wavelength-converted to a desired wavelength (532 nm) and emitted outside.

  Since the base substrate 14 and the cover part 16B are thermally separated by the heat insulating member 15, the heat of the fundamental wave laser part is hardly transmitted to the wavelength conversion element 3 through the cover part 16B. The base substrate 14 of the fundamental wave laser unit is controlled to be cooled by the cooling unit 100, and the temperature of the wavelength conversion element 3 is set to a desired value through the cover unit 16B by the Peltier element 110 provided as a temperature adjusting element in the cover unit 16B. Since the temperature is maintained, the temperature of the wavelength conversion element 3 can be stabilized, and the wavelength-converted wavelength: 532 nm laser light can be stably output.

  Further, the light converging lens 5 allows the laser light from the laser material 6 to be taken into the wavelength conversion element 3 by approximately 100%, thereby increasing the light utilization efficiency. Since the condenser lens 5 is “fixed to the same cover portion 16B as the wavelength conversion element 3 is fixed”, the optical axes of the condenser lens 5 and the wavelength conversion element 3 can be easily aligned, and the same cover portion 16B. Therefore, there is no position shift due to thermal expansion of the cover portion 16B, and the wavelength-converted laser beam can be output stably.

  As a modification of the third embodiment, instead of the cover portion 16B, the cover portion 16A of the second embodiment shown in FIG. 2 is used, and the temperature between the cover portion 16A and the wavelength conversion element 3 held by the cover portion 16A is changed. An adjustment element 13 may be interposed, and the temperature of the wavelength conversion element 3 may be directly adjusted by the temperature adjustment element 13.

FIG. 4 is a diagram for explaining the fourth embodiment. In order to avoid complications, the same reference numerals as in FIG.
In the fourth embodiment, similarly to the third embodiment, the condensing lens 5 is provided as a condensing element for condensing the laser light from the laser material 6 toward the light modulation element 3. The optical lens 5 is fixedly held by a lens holder 12 formed on the base substrate 14. Therefore, in Example 4, the lens holder 12 and the condenser lens 5 form a part of the fundamental wave laser unit. The configuration on the cover 16 side is the same as the configuration in the first embodiment.

  The condensing lens 5 is held between the laser material 6 and the wavelength conversion element 3 by the lens holder 12, and the fundamental laser beam from the laser material 6 is beamed “near the central portion in the longitudinal direction of the wavelength conversion element 3”. The light is condensed so as to form a waist and is incident on the wavelength conversion element 3. The laser light incident on the wavelength conversion element 3 in this way is wavelength-converted to a desired wavelength (532 nm) and emitted outside.

  Since the base substrate 14 and the cover part 16 are thermally separated by the heat insulating member 15, it is difficult for the heat of the fundamental wave laser part to reach the wavelength conversion element 3 through the cover part 16. The base substrate 14 of the fundamental wave laser unit is controlled to be cooled by the cooling unit 100, and the temperature of the wavelength conversion element 3 is set to a desired value through the cover unit 16 by the Peltier element 110 provided as a temperature adjusting element in the cover unit 16. Since the temperature is maintained, the temperature of the wavelength conversion element 3 can be stabilized, and the wavelength-converted wavelength: 532 nm laser light can be stably output.

  Further, the light converging lens 5 allows the laser light from the laser material 6 to be taken into the wavelength conversion element 3 by approximately 100%, thereby increasing the light utilization efficiency.

  As a modification of the fourth embodiment, the cover portion 16A of the second embodiment shown in FIG. 2 is used instead of the cover portion 16, and the temperature between the cover portion 16A and the wavelength conversion element 3 held by the cover portion 16A is changed. An adjustment element 13 may be interposed, and the temperature of the wavelength conversion element 3 may be directly adjusted by the temperature adjustment element 13.

  In addition, the lens holder 12 that holds the condenser lens 5 in a fixed manner can be “movable in the optical axis direction of the condenser lens 5”. For example, temperature conditions and thermal conditions can be obtained by well-known autofocus control or the like. The position of the condensing lens 5 may be adjusted according to the change of the laser beam so that the laser light from the laser material 6 is always condensed at the central portion in the longitudinal direction of the wavelength conversion element 3.

  FIG. 5 is a diagram for explaining the fifth embodiment and its modification. In order to avoid complication, the same reference numerals as in FIGS. 1 to 4 are appropriately attached to those that are not likely to be confused.

FIG. 5A is a diagram for explaining the fifth embodiment.
In the fifth embodiment, the configuration of the fundamental laser unit is the same as in the first to third embodiments.

  As shown in the drawing, the cover portion 16C is formed with a thick wall on the left half side and a thin wall on the right half side, and a boundary portion between the thick wall portion and the thin wall portion is formed on an inclined surface. The provided flat mirror 7 is positioned on the optical path of the fundamental laser beam from the laser material 6, bends the optical path by 90 degrees, and advances the reflected laser beam to the right in the figure. The bent optical path passes through the wavelength conversion element 3 provided in the thin portion of the cover portion 16C and passes through the emission window 4 opened on the side surface of the cover portion 16C.

  The fundamental laser beam from the laser material 6 is reflected by the plane mirror 7, then enters the wavelength conversion element 3, is converted into a desired wavelength (532 nm), passes through the emission window 4, and is emitted to the outside.

Since the base substrate 14 and the cover part 16C are thermally separated by the heat insulating member 15, the heat of the fundamental wave laser part is difficult to reach the wavelength conversion element 3 through the cover part 16C. The base substrate 14 of the fundamental wave laser unit is controlled to be cooled by the cooling unit 100, and the temperature of the wavelength conversion element 3 is set to a desired value through the cover unit 16 by the Peltier element 110 provided as a temperature adjusting element in the cover unit 16C. Since the temperature is maintained, the temperature of the wavelength conversion element 3 can be stabilized, and the wavelength-converted wavelength: 532 nm laser light can be stably output.
Further, by arranging the plane mirror 7 as the optical path bending element, the wavelength conversion element 3 can be placed horizontally, and the height (in the vertical direction in FIG. 5A) of the solid-state laser apparatus can be reduced. Can be downsized.

FIGS. 5B to 5D are diagrams showing a modification of the fifth embodiment of FIG.
In the example shown in FIG. 5B, a Peltier element 13A is interposed as a “temperature adjustment element” between the cover portion 16D and the wavelength conversion element 3, and the temperature of the wavelength conversion element 3 is directly adjusted by the temperature adjustment element 13A. Adjusted to Compared to the case of the fifth embodiment, the temperature adjustment element 13A directly adjusts the temperature of the wavelength conversion element 3, so that the temperature of the wavelength conversion element 3 is made "higher accuracy" than in the case of the fifth embodiment. Can be adjusted.

  In the example shown in FIG. 5C, the condensing lens 5 is arranged as a condensing element between the flat mirror 7 held by the cover part 16C of Example 5 and the wavelength conversion element 3, and the cover part 16C This is an example of holding. By providing the condensing lens 5, the laser light from the laser material 6 can be taken into the wavelength conversion element 3 approximately 100%, and the light utilization efficiency is increased.

  The example shown in FIG. 5 (d) is an example in which the cover portion 16C in the fifth embodiment shown in FIG. 5 (a) and the fundamental wave laser portion in the fourth embodiment shown in FIG. Is fixedly held by a lens holder 12 formed on the base substrate 14. As described with reference to the fourth embodiment, the lens holder 12 that holds the condenser lens 5 in a fixed manner is “movable in the optical axis direction of the condenser lens 5”. The position of the condensing lens 5 may be adjusted according to the change in the thermal conditions so that the laser light from the laser material 6 is always condensed at the central portion in the longitudinal direction of the wavelength conversion element 3.

  Instead of the cover portion 16C in FIG. 5 (d), a cover portion 16D shown in FIG. 5 (b), or a cover portion 16C shown in FIG. Of course.

  In each of the examples shown in FIGS. 5A to 5D, since the base substrate 14 and the cover portion are thermally separated by the heat insulating member 15, the heat of the fundamental laser portion is transmitted through the cover portion and wavelength conversion is performed. It is difficult to reach the element 3. The base substrate 14 of the fundamental wave laser unit is controlled to be cooled by the cooling means 100, and the temperature of the wavelength conversion element 3 is directly or directly through the cover unit by a Peltier element 110 provided as a temperature adjusting element in the cover unit. Is maintained at a desired temperature, the temperature of the wavelength conversion element 3 can be stabilized, and the wavelength-converted wavelength: 532 nm laser light can be stably output.

FIG. 6 is a diagram for explaining the sixth embodiment. In order to avoid complication, the same reference numerals as in FIGS. 1 to 5 are appropriately attached to those that are not likely to be confused.
The fundamental wave laser unit in the sixth embodiment is the same as that in the first to third embodiments.

  As shown in the figure, the cover portion 16E is formed with a thick wall on the left half side and a thin wall on the right half side, and is provided as a “light path bending element that doubles as a condensing element” at the boundary between the thick wall portion and the thin wall portion. The concave mirror 10 is positioned on the optical path of the laser beam from the laser material 6, bends the optical path by 90 degrees, and advances the reflected laser beam to the right in the figure. The bent optical path passes through the wavelength conversion element 3 provided in the thin portion of the cover portion 16C and penetrates the emission window 4 opened on the side surface of the cover portion 16C.

  The fundamental laser beam from the laser material 6 is reflected by the concave mirror 10, then enters the wavelength conversion element 3 while being focused by the condensing function of the concave mirror 10, and is focused on the central portion in the longitudinal direction of the wavelength conversion element 3. The wavelength is converted to a desired wavelength (532 nm), passes through the exit window 4 and exits to the outside.

  Since the base substrate 14 and the cover part 16E are thermally separated by the heat insulating member 15, the heat of the fundamental wave laser part is hardly transmitted to the wavelength conversion element 3 through the cover part 16E. The base substrate 14 of the fundamental wave laser unit is controlled to be cooled by the cooling unit 100, and the temperature of the wavelength conversion element 3 is set to a desired value through the cover unit 16E by the Peltier element 110 provided as a temperature adjusting element in the cover unit 16E. Since the temperature is maintained, the temperature of the wavelength conversion element 3 can be stabilized, and the wavelength-converted wavelength: 532 nm laser light can be stably output.

  Further, by arranging the concave mirror 10 as the optical path bending element, the laser light from the laser material 6 can be taken into the wavelength conversion element 3 by approximately 100%, and the light use efficiency is improved, and the wavelength conversion element 3 is placed horizontally. Since the height of the solid-state laser device (in the vertical direction in FIG. 6) can be reduced, the solid-state laser device can be downsized. In addition, the wavelength conversion element 3 can also be made to perform temperature adjustment directly using the Peltier element 13A like the example shown in FIG.5 (b).

FIG. 7 is a diagram for explaining the seventh embodiment. In order to avoid confusion, the same symbols as in FIG.
The difference from the sixth embodiment is that the concave mirror 18 is fixed by a cover portion 16E via a Peltier element 13B that is a temperature adjusting element. The concave mirror 18 is “a concave mirror whose curvature can be changed by heat”. Therefore, the condensing action of the concave mirror 18 can be adjusted by changing the temperature of the concave mirror 18 by the Peltier element 13B.

  The laser light from the laser material 6 is bent by the concave mirror 18, and is “converged by temperature control by the temperature adjusting element 13 </ b> B” so that the beam waist comes near the center in the longitudinal direction of the wavelength conversion element 3. The light is condensed and incident on the wavelength conversion element 3, converted in wavelength, passes through the exit window 4, and exits to the outside.

Since the base substrate 14 and the cover part 16E are thermally separated by the heat insulating member 15, the heat of the fundamental wave laser part is hardly transmitted to the wavelength conversion element 3 through the cover part 16E. The base substrate 14 of the fundamental wave laser unit is controlled to be cooled by the cooling unit 100, and the temperature of the wavelength conversion element 3 is set to a desired value through the cover unit 16E by the Peltier element 110 provided as a temperature adjusting element in the cover unit 16E. Since the temperature is maintained, the temperature of the wavelength conversion element 3 can be stabilized, and the wavelength-converted wavelength: 532 nm laser light can be stably output.
In addition, by arranging the concave mirror 18 as the optical path bending element, the fundamental wave laser light from the laser material 6 can be taken into the wavelength conversion element 3 by about 100%, and the light use efficiency is improved, and the wavelength conversion element 3 is arranged laterally. Since the height of the solid-state laser device (in the vertical direction in FIG. 6) can be reduced, the solid-state laser device can be reduced in size. In addition, the wavelength conversion element 3 can also be directly temperature-controlled using the Peltier element 13A like the example shown in FIG.5 (b). Further, the condensing action of the concave mirror 18 is adjusted in accordance with changes in temperature conditions and thermal conditions so that the laser light from the laser material 6 is always condensed at the central portion in the longitudinal direction of the wavelength conversion element 3. be able to.

  In each of the first to seventh embodiments and the modifications described above, the semiconductor laser light is incident and excited from the side surface direction of the laser material 6, and the laser output (fundamental laser light) is obtained by the optical resonator. In the semiconductor laser excitation type solid-state laser device that converts the output wavelength by the wavelength conversion element 3, the wavelength conversion element 3 performs phase matching by the refractive index, and the fundamental wave laser unit and the wavelength conversion element are thermally separated. The solid-state laser device (Claim 1) is configured to separately control the temperature thereof, and the wavelength conversion element 3 is fixed to the cover part 16 or the like that covers the fundamental laser part (Claim 2). In the example of Example 2 and FIG. 5B, the temperature adjusting elements 13 and 13A are interposed between the wavelength conversion element 3 and the cover part (Claim 3), Example 3, Example of FIG. In Examples 6 and 7, the wave from the fundamental laser part The laser light directed to the conversion element 3 having a light collecting element 5,10,18 for focusing (claim 4).

  Moreover, in the example of Example 4 and FIG.5 (d), the condensing element 5 is provided in the fundamental wave laser part side (Claim 5), Example 3, Example of FIG.5 (c), Example 6, 7, the condensing elements 5, 10, 18 are provided on the cover side (Claim 6). Furthermore, in Example 5 and its modified examples (FIGS. 5B to 5D) and Examples 6 and 7, the optical path bending element 7 that bends the optical path of the laser light from the fundamental wave laser unit to the wavelength conversion unit 3, In Examples 6 and 7, the optical path bending elements 10 and 18 have a condensing function, and also serve as a condensing element that condenses the laser light traveling from the fundamental wave laser unit to the wavelength conversion element ( (Claim 8) In Embodiment 7, the condensing element 18 that condenses the laser beam traveling from the fundamental wave laser unit to the wavelength conversion element can adjust the condensing function (Claim 9), and Example 5 and its In the modification examples 6 and 7, the optical path bending elements 7, 10, 18 are provided on the cover side (claim 10), and the optical path bending element 18 in the seventh embodiment has a light collecting function that can be adjusted by temperature. In addition, a temperature adjusting element 13B is interposed between the cover portion (claim) 11). In each of the embodiments and modifications described above, the optical resonator is formed of a reflective film formed on the opposing surface of the laser material 6 (claim 12).

  FIG. 8 is a view for explaining the concept of the laser device system of the present invention (claim 13). The fundamental wave laser unit 81 is as described above in connection with each embodiment. The temperature is detected by the temperature sensor 84 and controlled by a temperature controller (comprising a microcomputer or the like) 88 based on the detection result. Cooled by the cooling means 86. The cooling means 86 corresponds to that described as the cooling means 100 in the above embodiments.

  The LD driver 83 is means for driving the semiconductor laser for excitation light in the fundamental wave laser unit 81. The wavelength conversion element 82 corresponds to that described as the wavelength conversion element 3 in each of the above embodiments, and the temperature is detected by the temperature sensor 85, and the temperature controller 87 is controlled by the temperature controller 88 based on the result. (In the above examples, the Peltier elements 110, 13, 13A, and 13B correspond to this).

  To add a little, the example in which two semiconductor lasers are used to excite the laser material has been described. However, one or more semiconductor lasers may be used, and the laser light from the semiconductor laser array may be used. It may be excited.

  The concave mirror 18 having a variable curvature described in the seventh embodiment is “changes the curvature by heat”, but is not limited to this, for example, a system in which a concave mirror is provided in a bimorph type piezoelectric element to electrically change the curvature. A thing may be used. The various elements described in the above embodiments may be combined with each other.

FIG. 3 is a diagram for explaining Example 1; FIG. 6 is a diagram for explaining a second embodiment. FIG. 10 is a diagram for explaining Example 3; FIG. 10 is a diagram for explaining Example 4; It is a figure for demonstrating Example 5 and its modification. FIG. 10 is a diagram for explaining Example 6; FIG. 10 is a diagram for explaining Example 7; It is a figure for demonstrating a laser apparatus system.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1A, 1B Semiconductor laser 2A, 2B Excitation light condensing lens 3 Wavelength conversion element 6 Laser material 100 Cooling means 110 Peltier element

Claims (13)

In a semiconductor laser excitation type solid-state laser device that pumps a semiconductor laser beam incident from the side direction of the laser material, obtains a laser output by an optical resonator, and converts the wavelength of the obtained laser output by a wavelength conversion element,
The wavelength conversion element performs phase matching by refractive index,
A solid-state laser device characterized in that a fundamental wave laser unit and a wavelength conversion element are thermally separated and temperature controlled separately. The solid-state laser device according to claim 1,
A fixed laser device, wherein the wavelength conversion element is fixed to a cover portion covering the fundamental wave laser portion. The solid-state laser device according to claim 2,
A solid-state laser device comprising a temperature adjusting element interposed between a wavelength converting element and a cover portion. The solid-state laser device according to any one of claims 1 to 3,
A solid-state laser device comprising a condensing element that condenses laser light traveling from a fundamental wave laser unit toward a wavelength conversion element. The solid-state laser device according to claim 4,
A solid-state laser device, wherein the condensing element is provided on the fundamental wave laser unit side. The solid-state laser device according to claim 4,
A solid-state laser device characterized in that a condensing element is provided on the cover side. The solid-state laser device according to any one of claims 1 to 6,
A solid-state laser device comprising: an optical path bending element that bends an optical path of laser light directed from a fundamental wave laser unit to a wavelength conversion unit. The solid-state laser device according to claim 7, wherein
A solid-state laser device characterized in that the optical path bending element has a condensing function and also serves as a condensing element for condensing laser light from the fundamental wave laser unit toward the wavelength conversion element. The solid-state laser device according to any one of claims 4 to 8,
A solid-state laser device comprising a condensing element that condenses laser light traveling from a fundamental wave laser unit toward a wavelength conversion element, wherein the condensing element can adjust a condensing function. The solid-state laser device according to claim 7, 8 or 9,
A solid-state laser device characterized in that an optical path bending element is provided on the cover side. The solid-state laser device according to claim 10,
A solid-state laser device, wherein the optical path bending element has a condensing function that can be adjusted by temperature, and a temperature adjusting element is interposed between the optical path bending element and the cover. The solid-state laser device according to any one of claims 1 to 11,
A solid-state laser device, characterized in that the optical resonator is composed of a reflective film formed on the opposite surface of the laser material.   A laser device system using the solid-state laser device according to any one of claims 1 to 12.

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